Polyphenols have found applications in various fields, such as pharmaceuticals, cosmetics, and foods, because of their properties.
Piceatannol, for example, is a stilbene compound which is a type of polyphenols. It is contained in the seeds of the passion fruit, i.e., a fruit of the Passiflora genus in the Passifloraceae family, and has been reported to suppress the production of melanin, a major cause of brown spots, freckles, and pigmentation owing to sunburn (Japanese patent laid-open No. 2009-102298).
Piceatannol is also found in Rhodomyrtus tomentosa and Callistemon rigidus genera, which are small and large evergreen shrubs, respectively, in the Myrtaceae family. Extracts from these shrubs have a positive effect on recovery from UV damage and an inhibitory effect on MMP-2. It has been reported that piceatannol is the active ingredient in such extracts (Japanese patent laid-open No. 2012-46448; Kenroh Sasaki et al., Journal of Tohoku Pharmaceutical University, 57, 61-65 (2010)).
In use, polyphenols are often processed by inclusion complexation with cyclodextrin (CD) to improve solubility, absorption, and taste. For example, the water solubility and intestinal absorption of stilbenes was improved by encapsulation in α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), or a mixture of α-CD, β-CD and γ-cyclodextrin (γ-CD) (Japanese patent laid-open No. 2000-344622). The bitter taste of polyphenols was suppressed by inclusion complexation with a highly branched cyclodextrin (Japanese patent laid-open No. 2011-162539).
To use polyphenols in various fields, they have been purified from plant extracts using experimental equipment for enzyme addition, adsorption, and filtration (Japanese patent laid-open No. 2013-021950).